# def pascal_triangle(num):
#     list=[1]
#     for i in range(1,num):
#         list.insert(0,0)
#         # print(list)
#         for j in range(i):
#             list[j]=list[j]+list[j+1]
#
#
#     return list
# print(pascal_triangle(4))


# from random import randint as r
# for i in range(10):
#     print(max(r(1,10),i))

# x=[1,2,3,4,5,6,7]
# print(x[:5])
# print(x[5:])
# print(x[:5]+x[5:])
#
#

# import random
# x = [random.randint(0, 100) for i in range(20)]
# print(x)
# y = x[0 : 10]
# y.sort()
# x[0 : 10] = y
# y = x[10 : 20]
# y.sort(reverse=True)
# x[10 : 20] = y
# print(x)


# from random import randint as r
# list=[r(0,100) for i in range(20)]
# print(list)
# list_before=list[0:10]
# list_before.sort()
# print(list_before)
# list_after=list[::-1]
# list_after=list_after[:10]
# list_after.sort()
# print(list_after)
# print(list_before+list_after)

# #阶乘
# def func(n):
#     sum=0
#     temp=1
#     for i in range(1,n+1):
#         temp*=i
#         sum+=temp
#     return sum
# print(func(4))

#统计字符串
def func():
    newstr=""
    str=input("请输入一个字符串：")
    for s in str:
        if s not in newstr:
            newstr+=s
    list1=list(newstr[::-1])
    print(list1)
func()

